Friday, January 13, 2006
Cutoffs
Steve Scolnik @ 5:05 PM
Note: The Afternoon Update was delayed to get a glimpse of the latest model output from this afternoon's data. The pixels are still drying on the charts as we go to press.
It's not quite warm enough to wear cutoffs in the Washington DC area today (except perhaps for some transplanted California dudes or dudettes). Increasing clouds and some persistent fog have caused wide contrasts in temperatures across the region. In the immediate metro area, many locations were in the low 60s at mid afternoon, but the major airports were still in the upper 50s; Dulles did break through to 61 at 4pm. To the east, Andrews AFB was 63 while Annapolis was only 46 with fog and a southeast wind off the Bay. Further east, Salisbury was 66 and Georgetown DE, 69. Humidity is quite high; dewpoints are generally in the 50s, which would not be out of place on a cool summer day.
Surface weather map on the right at 1pm today from HPC/NWS/NOAA
All of this was ahead of a deepening low pressure area moving through the Great Lakes, supported by a very vigorous upper-level trough. As the low and the trough move eastward, they will bring showers and the chance of thunderstorms to our area tonight. The real forecast problem is what happens later in the day Saturday and at night as much colder air drives southward along the Atlantic coast. The models have been ambivalent about this. Some forecasts have called for the development of a "cutoff" upper level low, which would tend to prolong the precipitation until after the cold air had more fully arrived. More recent output indicates, however, that the precipitation will be pretty much out of here by early tomorrow afternoon, except for some leftover showers or flurries, and that the freezing line east of the mountains will pretty much coincide with the back edge of the precipitation. That's the solution we favor here at ABC (Afternoon Blog Central). Tune in to the comments section for alternative opinions and/or updates and to Jason's posts over the weekend.
One possible model solution (cutoff low) for 500 mb height and vorticity Saturday evening from NCEP/NWS/NOAA
Tonight and Tomorrow
Showers and possible thunderstorms are likely tonight with lows around 48. Tomorrow will see early highs around 50 and temperatures steady or dropping through the day to the low 40s by evening, with a 50% chance of showers.
Creature Feature
Today's Talk of the Nation SciFri show on NPR had an interview with Andrew Blaustein, director, graduate program in environmental sciences, professor of zoology, Oregon State University, about the frog extinction story we described yesterday. Audio is scheduled to be posted on their web page around 6pm. An article in the New York Times, "Frog Killer Is Linked to Global Warming" includes some criticism of the results.
It's not quite warm enough to wear cutoffs in the Washington DC area today (except perhaps for some transplanted California dudes or dudettes). Increasing clouds and some persistent fog have caused wide contrasts in temperatures across the region. In the immediate metro area, many locations were in the low 60s at mid afternoon, but the major airports were still in the upper 50s; Dulles did break through to 61 at 4pm. To the east, Andrews AFB was 63 while Annapolis was only 46 with fog and a southeast wind off the Bay. Further east, Salisbury was 66 and Georgetown DE, 69. Humidity is quite high; dewpoints are generally in the 50s, which would not be out of place on a cool summer day.Surface weather map on the right at 1pm today from HPC/NWS/NOAA
All of this was ahead of a deepening low pressure area moving through the Great Lakes, supported by a very vigorous upper-level trough. As the low and the trough move eastward, they will bring showers and the chance of thunderstorms to our area tonight. The real forecast problem is what happens later in the day Saturday and at night as much colder air drives southward along the Atlantic coast. The models have been ambivalent about this. Some forecasts have called for the development of a "cutoff" upper level low, which would tend to prolong the precipitation until after the cold air had more fully arrived. More recent output indicates, however, that the precipitation will be pretty much out of here by early tomorrow afternoon, except for some leftover showers or flurries, and that the freezing line east of the mountains will pretty much coincide with the back edge of the precipitation. That's the solution we favor here at ABC (Afternoon Blog Central). Tune in to the comments section for alternative opinions and/or updates and to Jason's posts over the weekend.One possible model solution (cutoff low) for 500 mb height and vorticity Saturday evening from NCEP/NWS/NOAA
Tonight and Tomorrow
Showers and possible thunderstorms are likely tonight with lows around 48. Tomorrow will see early highs around 50 and temperatures steady or dropping through the day to the low 40s by evening, with a 50% chance of showers.Creature Feature
Today's Talk of the Nation SciFri show on NPR had an interview with Andrew Blaustein, director, graduate program in environmental sciences, professor of zoology, Oregon State University, about the frog extinction story we described yesterday. Audio is scheduled to be posted on their web page around 6pm. An article in the New York Times, "Frog Killer Is Linked to Global Warming" includes some criticism of the results.
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